1. Field of the Invention
This invention relates to a yarn releasing apparatus for use with an automatic winder wherein a large number of yarns of yarn supply bobbins produced, for example, on a ring spinning frame are pieced and taken up onto a single cone- or cheese-shaped take-up package while removing defective portions of them such as slubs, and particularly to an auxiliary yarn releasing apparatus which can cope with taking up of yarns of a thick yarn number count.
2. Related Art Statement
An automatic winder includes a large number of spindles of winding units disposed in parallel to each other, and a mechanical arrangement of one of such spindles will be described with reference to FIG. 5.
Referring to FIG. 5, a winding unit 1 is fixed in position by a support pipe 2 and a duct 3, and a yarn Y, drawn out from a yarn supply bobbin 4, supplied to and positioned at a predetermined position of the unit passes a balloon braker 6, a tenser 7, of the disk or gate type, for applying a predetermined tension, a slub catcher 8 for detecting a defective portion of a yarn, and so forth, and is taken up onto a take-up package 14 which is rotated by a traverse drum 13. Reference numeral 15 denotes a yarn joining apparatus, 16 a suction mouth for guiding an upper yarn on the package side to the yarn joining apparatus 15, and 17 a relay pipe for guiding a lower yarn on the yarn supply bobbin side, to the yarn joining apparatus 15. Each winding unit includes the members mentioned above, and a large number of such winding units 1 are provided in parallel to each other to construct an automatic winder. Meanwhile, yarn supply bobbins 4 are supplied to a re-winding position A of the winding unit 1 by way of a supply conveyor 11 and a rotary disk 19 while they remain in a condition wherein they are fitted individually on independent trays 18. Then, an empty bobbin 4' from which taking up of a yarn has been completed, is discharged to a discharge conveyor 12, and a new yarn supply bobbin 4 is supplied instead. It is to be noted that a yarn end Y1 is inserted in a hollow at a top portion of a yarn supply bobbin 4 positioned at the winding position A so that the yarn Y of the yarn supply bobbin 4 may be blown up and sucked into the suction pipe 17.
By the way, the yarn Y released from a chase portion 4a is ballooned until it reaches a balloon guide 10. As a result of the ballooning, the yarn releasing force is increased and may cause a yarn break. Consequently, as shown in FIG. 5, a balloon of the yarn released from the yarn supply bobbin 4 is limited by means of the balloon braker 6 in the form of a tube of a quadrangular prism to keep the shape of the balloon at the yarn releasing portion to a suitable shape.
Since the balloon braker 6 is positioned above the yarn supply bobbin 4, from the lower side of the guide plate 10, and is secured to a machine frame 5, as the yarn releasing operation of the yarn supply bobbin 4 proceeds, the distance from the chase portion 4a of the yarn supply bobbin 4 to the lower end of the balloon braker 6 increases gradually, and there is a tendency that the operation of the balloon braker 6 becomes worse. Therefore, it is also proposed that, as shown in FIG. 6, the balloon braker 6 is formed as a cylinder and is moved down gradually following releasing of the yarn of a yarn supply bobbin. In particular, the balloon braker 6 moves down, following releasing of the yarn, from a start position at which the lower end of the balloon braker 6 covers a little over a take-up tube 4b to a lower limit position of a solid line so that the balloon brake 6 may be put over the take-up tube 4b to maintain the distance L from the lower end of the balloon braker 6 to the chase 4a to an appropriate value. Accordingly, even when the last end of winding approaches, the condition wherein the balloon is limited is maintained.
If a yarn of a thick yarn number count (for example, a thicker yarn than a yarn having a meter number count Nm 20) is rewound using the auxiliary yarn releasing apparatus of FIG. 6, described in the prior art, then there is a problem in that the centrifugal force acting upon the yarn becomes so high that the yarn released from the chase portion 4a enters the balloon braker 6 (particularly a balloon of the yarn A released from a lower portion of the chase portion 4a becomes large as shown at A) and the variation of the yarn releasing tension increases as the absolute value of the yarn releasing tension increases. Further, while there is an example wherein a small umbrella is provided at an entrance of the balloon braker 6, a balloon further expands from an outer edge of the umbrella, which reversely makes a cause of a rise of the tension.
The present invention has been accomplished during experimental investigation for causes from which such problems of the prior art arise.